System for continuously manufacturing composite structure

ABSTRACT

A system is disclosed for use in additively manufacturing a composite structure. The system may include at least one support, and a print head operatively connected to the at least one support and configured to discharge composite material. The system may further include an auxiliary tool operatively connected to the at least one support and configured to receive the composite material discharged by the print head.

RELATED APPLICATIONS

This application is a continuation of U.S. Non-Provisional applicationSer. No. 16/279,955 that was filed on Feb. 19, 2019, which is based onand claims the benefit of priority from United States ProvisionalApplication Nos. 62/656,866 that was filed on Apr. 12, 2018 and62/730,541 that was filed on Sep. 13, 2018, the contents of all of whichare expressly incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates generally to a manufacturing system and,more particularly, to a system for continuously manufacturing compositestructures.

BACKGROUND

Continuous fiber 3D printing (a.k.a., CF3D™) involves the use ofcontinuous fibers embedded within a matrix discharging from a moveableprint head. The matrix can be a traditional thermoplastic, a powderedmetal, a liquid resin (e.g., a UV curable and/or two-part resin), or acombination of any of these and other known matrixes. Upon exiting theprint head, a head-mounted cure enhancer (e.g., a UV light, anultrasonic emitter, a heat source, a catalyst supply, etc.) is activatedto initiate and/or complete curing of the matrix. This curing occursalmost immediately, allowing for unsupported structures to be fabricatedin free space. When fibers, particularly continuous fibers, are embeddedwithin the structure, a strength of the structure may be multipliedbeyond the matrix-dependent strength. An example of this technology isdisclosed in U.S. Pat. No. 9,511,543 that issued to Tyler on Dec. 6,2016 (“the '543 patent”).

Although CF3D™ provides for increased strength, compared tomanufacturing processes that do not utilize continuous fiberreinforcement, improvements can be made to the structure and/oroperation of existing systems. The disclosed additive manufacturingsystem is uniquely configured to provide these improvements and/or toaddress other issues of the prior art.

SUMMARY

In one aspect, the present disclosure is directed to a system foradditively manufacturing a composite structure. The system may includeat least one support, and a print head operatively connected to the atleast one support and configured to discharge composite material. Thesystem may further include an auxiliary tool operatively connected tothe at least one support and configured to receive the compositematerial discharged by the print head.

In another aspect, the present disclosure is directed to another systemfor additively manufacturing a composite structure. This system mayinclude a support, and a print head operatively connected to the supportand configured to discharge composite material. The system may alsoinclude at least one of a conveyor belt and a roller operativelyconnected to the support and configured to receive the compositematerial discharged by the print head. The at least one of the conveyorbelt and roller is configured to selectively move from a stowed positionto an engaged position at a discharge location of the print head.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is diagrammatic illustration of an exemplary disclosed additivemanufacturing system; and

FIGS. 2, 3, and 4 are diagrammatic illustrations of exemplary disclosedend effectors that may be used in conjunction with the additivemanufacturing system of FIG. 1.

DETAILED DESCRIPTION

FIG. 1 illustrates an exemplary system 10, which may be used tocontinuously manufacture composite structures 12 having any desiredcross-sectional shape (e.g., circular, rectangular, or polygonal).System 10 may include at least one support and at least one end-effectorcoupled to and moved by the at least one support. In the disclosedembodiment of FIG. 1, two different supports are shown, including afirst support 14, and a second support 16 that is separate and distinctfrom first support 14. In this example, both of first and secondsupports 14, 16 are robotic arms (e.g., the same types of or differentarms) capable of moving the respective end-effectors in multipledirections during fabrication of structure 12. Support 14 and/or support16 may alternatively embody an overhead gantry or a hybrid gantry/armalso capable of moving the respective end-effector(s) in multipledirections during fabrication of structure 12.

A first end-effector 18 may be operatively connected to support 14; anda second end-effector 20 may be operatively connected to support 16. Inthe example of FIG. 1, end-effector 18 is a print head configured todischarge a composite material, and end-effector 20 is an auxiliary toolthat cooperates with the print head during fabrication of structure 12.For the purposes of this disclosure, the terms end-effector 18 and head18 will be used interchangeably. Likewise, the terms end-effector 20 andtool 20 will be used interchangeably.

Head 18 may be configured to receive or otherwise contain a matrixmaterial. The matrix material may include any type of matrix material(e.g., a liquid resin, such as a zero-volatile organic compound resin, apowdered metal, etc.) that is curable. Exemplary resins includethermosets, single- or multi-part epoxy resins, polyester resins,cationic epoxies, acrylated epoxies, urethanes, esters, thermoplastics,photopolymers, polyepoxides, thiols, alkenes, thiol-enes, and more. Inone embodiment, the matrix material inside head 18 may be pressurized ordepressurized, for example by an external device (e.g., by an extruderor another type of pump—not shown) that is fluidly connected to head 18via a corresponding conduit (not shown). In another embodiment, however,the pressure may be generated completely inside of head 18 by a similartype of device. In yet other embodiments, the matrix material may begravity-fed into and/or through head 18. For example, the matrixmaterial may be fed into head 18, and pushed or pulled out of head 18along with one or more continuous reinforcements. In some instances, thematrix material inside head 18 may need to be kept cool and/or dark inorder to inhibit premature curing or otherwise obtain a desired rate ofcuring after discharge. In other instances, the matrix material may needto be kept warm for similar reasons. In either situation, head 18 may bespecially configured (e.g., insulated, temperature-controlled, shielded,etc.) to provide for these needs.

The matrix material may be used to coat any number of continuousreinforcements (e.g., separate fibers, tows, rovings, socks, and/orsheets of continuous material) and, together with the reinforcements,make up a portion (e.g., a wall) of composite structure 12. Thereinforcements may be stored within or otherwise passed through head 18.When multiple reinforcements are simultaneously used, the reinforcementsmay be of the same material composition and have the same sizing andcross-sectional shape (e.g., circular, square, rectangular, etc.), or adifferent material composition with different sizing and/orcross-sectional shapes. The reinforcements may include, for example,carbon fibers, vegetable fibers, wood fibers, mineral fibers, glassfibers, metallic wires, optical tubes, etc. It should be noted that theterm “reinforcement” is meant to encompass both structural andnon-structural types of continuous materials that are at least partiallyencased in the matrix material discharging from head 18.

The reinforcements may be exposed to (e.g., at least partially coatedwith) the matrix material while the reinforcements are inside head 18,while the reinforcements are being passed to head 18, and/or while thereinforcements are discharging from head 18. The matrix material, dryreinforcements, and/or reinforcements that are already exposed to thematrix material may be transported into head 18 in any manner apparentto one skilled in the art. In some embodiments, a filler material (e.g.,chopped fibers) may be mixed with the matrix material before and/orafter the matrix material coats the continuous reinforcements.

One or more cure enhancers (e.g., a UV light, an ultrasonic emitter, alaser, a heater, a catalyst dispenser, a chiller, etc.) 19 may bemounted proximate (e.g., within, on, or adjacent) head 18 and configuredto enhance a cure rate and/or quality of the matrix material as it isdischarged from head 18. Cure enhancer 19 may be controlled toselectively expose portions of structure 12 to energy (e.g., UV light,electromagnetic radiation, vibrations, heat, a chemical catalyst, achilled medium, etc.) during the formation of structure 12. The energymay increase a rate of chemical reaction occurring within the matrixmaterial, sinter the material, harden the material, or otherwise causethe material to cure as it discharges from head 18. The amount of energyproduced by cure enhancer 19 may be sufficient to cure the matrixmaterial before structure 12 axially grows more than a predeterminedlength away from head 18. In one embodiment, structure 12 is completelycured before the axial growth length becomes equal to an externaldiameter of the matrix coated reinforcement.

The matrix material and/or reinforcement may be discharged from head 18via at least two different modes of operation. In a first mode ofoperation, the matrix material and/or reinforcement are extruded (e.g.,pushed under pressure and/or mechanical force) from head 18 as head 18is moved by support 14 to create the 3-dimensional trajectory within alongitudinal axis of structure 12. In a second mode of operation, atleast the reinforcement is pulled from head 18, such that a tensilestress is created in the reinforcement during discharge. In this mode ofoperation, the matrix material may cling to the reinforcement andthereby also be pulled from head 18 along with the reinforcement, and/orthe matrix material may be discharged from head 18 under pressure alongwith the pulled reinforcement. In the second mode of operation, wherethe matrix material is being pulled from head 18 with the reinforcement,the resulting tension in the reinforcement may increase a strength ofstructure 12 (e.g., by aligning the reinforcements, inhibiting buckling,equally distributing loads, etc.), while also allowing for a greaterlength of unsupported structure 12 to have a straighter trajectory. Thatis, the tension in the reinforcement remaining after curing of thematrix material may act against the force of gravity (e.g., directlyand/or indirectly by creating moments that oppose gravity) to providesupport for structure 12.

The reinforcement may be pulled from head 18 as a result of head 18moving away from an anchor point 22. In particular, at the start ofstructure formation, a length of matrix-impregnated reinforcement may bepulled and/or pushed from head 18, deposited onto anchor point 22, andcured such that the discharged material adheres (or is otherwisecoupled) to anchor point 22. Thereafter, head 18 may be moved away fromanchor point 22, and the relative movement may cause the reinforcementto be pulled from head 18. It should be noted that the movement ofreinforcement through head 18 could be assisted (e.g., via internal headmechanisms), if desired. However, the discharge rate of reinforcementfrom head 18 may primarily be the result of relative movement betweenhead 18 and anchor point 22, such that tension is created within thereinforcement. It is contemplated that anchor point 22 could be movedaway from head 18 instead of or in addition to head 18 being moved awayfrom anchor point 22.

It is also contemplated that, in some applications, the materialdischarging from head 18 may cure too slowly and/or be too weak forunsupported free-space printing. In these applications, it may bepossible to use tool 20 as a temporary mold for the material untiladequate curing has been achieved and/or until a sufficient number ofmaterial layers have been built up. That is, tool 20 may be moved andoriented by support 16 to a location below an intended free-spacetrajectory of the discharging material (e.g., in general axial alignmentwith head 18), such that the material can temporarily rest on tool 20.In some embodiments, tool 20 transfers heat and/or pressure to or awayfrom the material to allow the material to cure faster or to a greaterdepth while situated thereon. After the material cures to a sufficientdegree and/or after enough layers of material have been deposited, tool20 may be moved to another location and/or used in a different manner.This may allow for free-space printing without the need of permanent orcustomized molds.

Tool 20 may take any desired form that allows for temporary mold-likesupport of the material discharging from head 18. For example, tool 20may include a conveyor belt 24 (see FIGS. 1 and 2) and/or a roller 26(See FIGS. 3 and 4) onto which the material can be discharged. A motor28 or other actuator may be situated to selectively drive motion (e.g.,rotation) of conveyor belt 24 and/or roller 26 in coordination with themotion of support 14 and/or support 16. With this configuration, tool 20may always remain at the discharge location of head 18 during travel ofhead 18 along a predefined trajectory and the discharging material maybe deposited onto (and, in some instances pulled out by) a vacantportion of the rotating conveyor belt 24 or roller 26.

In some embodiments, conveyor belt 24 may be configured to flex or curland thereby impart a corresponding shape into the curing materialdischarged thereon. For example, conveyor belt 24 may have end-locatedrollers 30 around which a belt 32 passes, and any number of intermediaterollers 34 positioned between rollers 30. Rollers 30 and/or 34 may beselectively position-adjusted relative to each other to create either aflat surface onto which the material is discharged (see FIG. 2) or asimple or complex curved surface (see FIG. 1) having any number ofdesired radiuses and/or splines.

It is contemplated that, in some embodiments, head 18 may be selectivelyheld stationary (or moved less than tool 20), while tool 20 is moved,oriented, shaped, and/or rotated to continuously receive and place(e.g., pull and/or deposit) material discharged by head 18 in a desiredmanner. For example, head 18 may move at a first speed relative toanchor point 22 to cause material to be discharged (e.g., pulled) fromhead 18 at a first rate, while tool 20 moves at a second speed relativeto head 18 to affect (e.g., to increase) the rate at which the materialis discharged from head 18. In addition, a simple trajectory of head 18may combine with a simple trajectory of tool 20 to create a more complexdischarge trajectory of the composite material.

It is also contemplated that one or more cure enhancers 19 could beassociated with tool 20 instead of or in addition to cure enhancer(s) 19being associated with head 18. For example, the cure enhancer(s) 19associated with head 18 may be sufficient to only partially cure andstiffen the discharging material, yet still allow some manipulation ofthe material. In addition, any cure enhancer(s) 19 associated with tool20 may further cure and stiffen the discharging material, such that thematerial remains at a location affected by tool 20.

A controller 36 may be provided and communicatively coupled with support14, support 16, head 18, any number of cure enhancers 19, and tool 20.Each controller 36 may embody a single processor or multiple processorsthat are configured to control an operation of system 10. Controller 36may include one or more general or special purpose processors ormicroprocessors. Controller 36 may further include or be associated witha memory for storing data such as, for example, design limits,performance characteristics, operational instructions, tool paths, andcorresponding parameters of each component of system 10. Various otherknown circuits may be associated with controller 36, including powersupply circuitry, signal-conditioning circuitry, solenoid drivercircuitry, communication circuitry, and other appropriate circuitry.Moreover, controller 36 may be capable of communicating with othercomponents of system 10 via wired and/or wireless transmission.

One or more maps may be stored in the memory of controller 36 and usedduring fabrication of structure 12. Each of these maps may include acollection of data in the form of lookup tables, graphs, and/orequations. In the disclosed embodiment, the maps may be used bycontroller 36 to determine the movements of head 18 and/or tool 20required to produce the desired size, shape, and/or contour of structure12, and to regulate operation of cure enhancers 19 in coordination withthe movements.

As shown in FIG. 2, in addition to tool 20 functioning as a rotating andmoving platform or variable mold onto which material from head 18 can becontinuously discharged, tool 20 may also provide resistance topressures generated by a compactor 38 that trails behind the dischargelocation (e.g., a nozzle) of head 18. In the disclosed example,compactor 38 is mounted to head 18 and includes a roller 40 that isbiased outward toward the material discharging from head 18. Whenprinting overlapping layers (e.g., when not into free-space), roller 40of compactor 38 may sandwich the discharging material between the rollersurface and a previously discharged surface of structure 12 toconsolidate fibers and/or remove voids. However, when printing into freespace, the discharging material may instead be sandwiched between roller40 and belt 32 or roller 26 (or smooth low-friction non-rotatingsurface—not shown) and thereby compressed.

It is contemplated that head 18 and tool 20 could be mounted to the samesupport (e.g., 14 or 16), if desired. An example of this arrangement isillustrated in FIG. 3. In this example, tool 20 may be pivotally mountedto head 18 and/or the associated support (e.g., support 14) at a pivotpoint 42, and only selectively deployed from a stowed position (e.g.,via an actuator 44 energized by controller 36) to an engaged position inanticipation of free-space printing. When printing overlapping layers,actuator 44 may be de-energized (or energized in a reverse manner) tomove tool 20 out of the way. It is contemplated that other means ofdeploying tool 20 may alternatively or additionally be utilized.

FIG. 4 illustrates a final exemplary embodiment of tool 20. In thisembodiment, tool 20 (a conveyor belt 24 or a roller 26) may be mountedto the same support as head 18 or to a different support via agyroscopic- or gimbal-like connector 48. Tool 20, in this embodiment,may be configured to trail behind head 18 and follow along a desiredtrajectory of structure 12, as laid out by head 18, without causingsignificant deviations from the trajectory. In particular, connector 48may allow conveyor belt 24 and/or roller 26 to rotate freely about oneor more axes 50 during pursuit of head 18 without imparting significantforces into structure 12. It is contemplated, however, that tool 20 maybe configured to selectively adjust and/or completely change thetrajectory of structure 12 (e.g., via one or more actuators associatedwith axes 50) prior to full curing, if desired. Compactor 38, in theembodiment of FIG. 4, may be an integral part of head 18 or tool 20. Inthe depicted example, roller 40 of compactor 38 is axially trappedbetween end flanges of roller 26, such that a desired alignment isalways maintained therebetween.

INDUSTRIAL APPLICABILITY

The disclosed systems may be used to continuously manufacture compositestructures having any desired cross-sectional shape and length. Thecomposite structures may include any number of different fibers of thesame or different types and of the same or different diameters, and anynumber of different matrixes of the same or different makeup. Operationof system 10 will now be described in detail.

At a start of a manufacturing event, information regarding a desiredstructure 12 may be loaded into system 10 (e.g., into controller 36 thatis responsible for regulating operations of support 14 and/or head 18).This information may include, among other things, a size (e.g.,diameter, wall thickness, length, etc.), a contour (e.g., a trajectory),surface features (e.g., ridge size, location, thickness, length; flangesize, location, thickness, length; etc.), connection geometry (e.g.,locations and sizes of couplings, tees, splices, etc.), desired surfacetextures, texture locations, etc. It should be noted that thisinformation may alternatively or additionally be loaded into system 10at different times and/or continuously during the manufacturing event,if desired. Based on the component information, one or more differentreinforcements and/or matrix materials may be selectively installedand/or continuously supplied into system 10. In some embodiments, thereinforcements may also need to be connected to a pulling machine (notshown) and/or to a mounting fixture (e.g., to an anchor point).Installation of the matrix material may include filling head 18 and/orcoupling of an extruder (not shown) to head 18.

The component information may then be used to control operation ofsystem 10. For example, the reinforcements may be pulled and/or pushedalong with the matrix material from head 18. Support 14 may alsoselectively move head 18 in a desired manner at the same time thatsupport 16 moves tool 20, such that an axis of the resulting structure12 follows a desired three-dimensional trajectory. Once structure 12 hasgrown to a desired length, structure 12 may be severed from system 10.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the disclosed systems. Otherembodiments will be apparent to those skilled in the art fromconsideration of the specification and practice of the disclosed system.For example, it is contemplated that instead of auxiliary tool 20 havinga rotating belt or roller, tool 20 may instead having a smoothlow-friction non-rotating surface that slides along below thedischarging material, if desired. In addition, it is contemplated thattool 20 may be used primarily or only at a time when a trajectory of thedischarging material changes significantly (e.g., turns a corner),wherein tool 20 is used as a temporary anchoring point at a cornerlocation (e.g., until enough layers have been built up to resistundesired movement away from the corner location without the temporarysupport). It is intended that the specification and examples beconsidered as exemplary only, with a true scope being indicated by thefollowing claims and their equivalents.

What is claimed is:
 1. A method of additively manufacturing a structure,comprising: discharging a material from a print head; moving the printhead during discharging to form the structure; moving an auxiliary toolto follow a trajectory of the print head and temporarily receive thematerial discharging from the print head; and thereafter moving theauxiliary tool away from the received material to continue following thetrajectory of the print head and receive additional material.
 2. Themethod of claim 1, wherein: moving the print head includes moving theprint head with a first support; and moving the auxiliary tool includesmoving the auxiliary tool with a second support.
 3. The method of claim1, wherein the auxiliary tool includes at least one of a conveyor beltand a roller onto which the material is discharged and the methodfurther includes activating the at least one of the conveyor belt andthe roller to discharge from the auxiliary tool the received material.4. The method of claim 3, wherein the auxiliary tool is a conveyor beltand the method further includes curling and thereby adjusting a shape ofthe material discharged thereon.
 5. The method of claim 3, wherein theauxiliary tool further includes a motor configured to drive rotation ofthe at least one of the conveyor belt and roller and the method includesselectively activating the motor.
 6. The method of claim 1, furtherincluding compacting the material against the auxiliary tool duringdischarge of the material into free space, wherein moving the auxiliarytool away from the received material includes moving the auxiliary toolaway from the received material after compaction and allowing thematerial to support itself in free space.
 7. The method of claim 6,wherein compacting the material includes pressing a compactor attachedto the print head against the material on the auxiliary tool.
 8. Themethod of claim 6, wherein compacting the material includes pressing acompactor attached to the auxiliary tool against the material on theauxiliary tool.
 9. The method of claim 1, wherein: moving the print headand moving the auxiliary tool includes moving a sngle support connectedto both the print head and the auxiliary tool; and the method furtherincludes selectively moving the auxiliary tool from a stowed position toan engaged position at a discharge location of the print head.
 10. Themethod of claim 1, further including allowing the auxiliary tool torotate freely about at least one axis when following the trajectory ofthe print head.
 11. The method of claim 1, further includingcoordinating motion of the auxiliary tool with motion of the print head,such that the auxiliary tool is maintained at a discharge location ofthe print head.
 12. The method of claim 1, further includingcoordinating motion of the auxiliary tool with motion of the print head,such that the auxiliary tool always trails behind a discharge locationof the print head.
 13. The method of claim 12, wherein: moving the printhead includes moving the print head relative to an anchor point todischarge material at a first rate; and moving the auxiliary toolincludes moving the auxiliary tool relative to the print head toincrease the first rate.
 14. The method of claim 1, wherein: the methodfurther includes exposing the material discharging from the print headto a cure energy; and moving the auxiliary tool away from the receivedmaterial includes moving the auxiliary tool away from the material afterthe material is at least partially cured.
 15. The method of claim 14,wherein exposing the material discharging from the print head to thecure energy includes activating a cure enhancer attached to theauxiliary tool.
 16. The method of claim 1, wherein moving the print headincludes causing a robotic arm to move the print head.
 17. A method foradditively manufacturing a structure, comprising: discharging a materialfrom a print head onto at least one of a conveyor belt and a rollertrailing behind the print head; moving a support connected to both theprint head and the at least one of the conveyor belt and the roller toolduring discharging to form the structure; causing the at least one ofthe conveyor belt and the roller to selectively move from a stowedposition to an engaged position at a discharge location of the printhead; and causing the at least one of the conveyor belt and the rollerto discharge the received material after the received material cansupport itself in free space.
 18. The method of claim 17, furtherincluding driving rotation of the at least one of the conveyor belt androller.
 19. The method of claim 17, further including compacting thematerial onto the at least one of the conveyor belt and roller, whereincausing the at least one of the conveyor belt and the roller todischarge the received material includes causing the at least one of theconveyor belt and the roller to discharge the received material afterthe received material is compacted.
 20. The method of claim 17, furtherincluding causing a first cure enhancer to at least partially cure thematerial at discharge, wherein causing the at least one of the conveyorbelt and the roller to discharge the received material includes causingthe at least one of the conveyor belt and the roller to discharge thereceived material after the received material is at least partiallycured.